The objective of the present study was to optimize the strategy for the treatment of the patients presenting with primary varicosis based on the results of the clinical and morphological investigation of the venous bed. Material and methods. A total of 68 patients participated in the study including 47 (69.1%) women at the age from 28 to 68 (mean 46,3±3,6) years. Thirty one (45,6%) of them presented with class С2 varicose vein disease, 26 (38,2%) and 11 (16,2%) with class C3 and С4 of this condition respectively. Two parts of the trunk of the great saphenous vein were taken from each patient during phlebectomy, viz. preosteal and near-ankle segments. One of them was used for the histological study, the other for the physiological study designed to evaluate the contractile activity. The perfusion solution was supplemented by the purified micronized fraction of flavonoids (PMFF) at a daily dose of 1,000 mg. Results. Three groups of observations were distinguished depending on the manifestations of the sclerotic changes in the venous wall: mild, moderate, and severe. The basal tone of the samples obtained from the patients of group 1 averaged 0.93±0.08 with the phase contraction amplitude being 0,021±0,0022 g and frequency 29,4±3,8/min. The same parameters in group 2 were 0,7±0,083 g and 0,019±0,0011 g, frequency 31,5±2,93/min and in group 3 — 0,34±0,018 g, 0,014±0,0028 g and frequency 18±2,47/min respectively. The addition of the purified micronized fraction of flavonoids to the perfusate during 60 s resulted in a marked rise of the basal tone by 30—50% and the increase of the phase contraction amplitude that persisted for at least 3 hours. These changes were especially well apparent in group 1 and less so in groups 2 and 3. Conclusion. The wall of the great saphenous vein in the patients presenting with varicose vein disease undergoes degenerative and dystrophic changes that deteriorate its biomechanical properties. The absence of such changes in the lower legs of many patients justifies the application of short stripping. The purified micronized fraction of flavonoids exhibits the strong phlebotoning action mediated through the elevation of the basal venous tone and the amplitude of its phase contractions.